In one typical configuration, a telecommunications system is housed within a chassis. In such a configuration, various cards are inserted into slots formed within the chassis. The chassis provides mechanical support and environmental, magnetic, and electrical protection and shielding for the cards inserted into the chassis. Typically, a backplane is housed within the chassis. The cards are coupled to the backplane so that the cards are able to communicate with one another over the backplane.
For example, in such a configuration, each card includes a connector (also referred to here as a “backplane connector”) that is coupled to a mating connector on the backplane (the latter connector is also referred to here as a “card connector”). Typically, the backplane includes multiple card connectors so that multiple cards can be coupled to the backplane.
In order for a card to be coupled to a backplane, the backplane connector of that card and a corresponding card connector of the backplane must be compatible (that is, mate together). When a new version of a backplane is released, in order for a previously released card (also referred to here as a “legacy card”) to be coupled to the new backplane, at least one of the card connectors of the new backplane must be compatible with the backplane connector of the legacy card. Otherwise, the legacy card will not be able to be coupled to the new backplane.
Similarly, when a new version of a card is released, in order for a previously released backplane (also referred to here as a “legacy backplane”) to be coupled to the new card, the backplane connector of the new card must be compatible with at least one of the card connectors of the legacy backplane. Otherwise, the new card will not be able to be coupled to the legacy backplane.